Designing Multi-Tenant SaaS with Django

Building multi-tenant applications requires careful consideration of data isolation, performance, and scalability. In this post, I'll share patterns I've used in production systems serving hundreds of tenants.

The Three Approaches

1. Shared Database, Shared Schema

All tenants share the same tables with a tenant_id column. Simple but requires careful query filtering.

class TenantMiddleware:
    def __call__(self, request):
        tenant = get_tenant_from_request(request)
        set_current_tenant(tenant)
        return self.get_response(request)

2. Shared Database, Separate Schemas

Each tenant gets their own PostgreSQL schema. Better isolation with moderate complexity.

3. Separate Databases

Complete isolation but highest operational overhead.

My Recommendation

For most SaaS applications, the shared schema approach with proper indexing and row-level security provides the best balance of simplicity and isolation.

Key Patterns

• Use Django's Manager classes to automatically filter by tenant
• Implement tenant context using thread-local storage or middleware
• Add composite indexes on (tenant_id, primary_lookup_field)
• Use connection pooling per tenant for heavy workloads

The key is starting simple and adding complexity only when scale demands it.